Temperature dependence of the thermal boundary conductance in Ag–3Si/diamond composites

• Description of thermal conductivity behaviour of Ag/diamond composites from 4 K up to ambient temperature.
• Surface termination plays a crucial role to improve thermal conductivity in diamond composites.
• Oxygen termination of diamond surfaces can be easily performed by wet chemical means (acid treatment).
• Calculation of thermal boundary conductances between Ag and diamond allows assessing the importance of diamond surface oxygenation.

The effect of oxygen termination of diamond surfaces on the interface thermal conductance between Ag–3Si and diamonds is investigated in dependence of temperature by measuring thermal conductivity in the temperature range from 4 K up to ambient. Composites for O-terminated diamonds exhibit a marked maximum of 960 W m− 1 K− 1 at roughly 150 K. Calculation of the interface conductance by the differential effective medium (DEM) scheme obtained marked difference between H- and O-terminated diamond surfaces in composites and is supported by AFM force distance measurements on native, H-terminated, and O-terminated diamond single crystal (100) surfaces. O-termination can be easily induced by immersing diamonds in hot aqua regia solution.